Flexible hermetic thin film with light extraction layer

ABSTRACT

A protected organic light emitting diode includes an organic light emitting diode structure formed on a substrate, a hermetic barrier layer formed over at least part of the organic light emitting diode structure, and a light extraction layer. The barrier layer may include a glass material such as a tin fluorophosphate glass, a tungsten-doped tin fluorophosphate glass, a chalcogenide glass, a tellurite glass, a borate glass or a phosphate glass. The light extraction layer, which may be formed over the barrier layer, includes a high refractive index matrix material and at least one of scattering particles dispersed throughout the matrix material and a roughened surface.

RELATED APPLICATIONS

The present disclosure is a continuation application of and claims thepriority benefit of co-pending U.S. application Ser. No. 13/751,638filed on Jan. 28, 2013, now U.S. Pat. No. 8,754,434, the entirety ofwhich is incorporated herein by reference.

BACKGROUND

The present disclosure relates generally to organic light emittingdiodes (OLEDs) and display devices that include OLEDs. Contemplateddisplay devices include, but are not limited to, light sources, imagedisplays, visual indicators, and other devices that utilize one or morelight sources to fulfill their function.

Although OLED devices can efficiently generate light, much of the lightthat is produced is not transmitted but remains trapped within thedevice. In many conventional devices, 25% or less of the light producedemanates from the device while 75% or more of the light is trappedwithin the device (45% or more trapped within the device's organiclayers, and 30% or more trapped within inorganic layers, i.e., glasssubstrate). A schematic illustration of a bottom-emission OLED device,where light emission occurs through the substrate, is shown in FIG. 1A.A schematic illustration of a top-emission OLED device is shown in FIG.1B. Each device includes a top electrode 2, one or more active layers 4,and a bottom electrode 6 formed over a supporting substrate 10. In abottom-emission device, the bottom electrode may be transparent, whilein a top-emission device, the top electrode may be transparent. Thearrows in each figure depict the direction of light emission.

In view of the foregoing, one aspect of the present disclosure relatesto improving the light transmission of organic light emitting diodes. Afurther aspect of the present disclosure relates to protecting organiclight emitting diodes from adverse reactions with air and/or moisture,thus extending their lifetime. The technology of the present disclosurecan be used to enhance the performance of organic light emitting diodes.

SUMMARY

Disclosed herein are materials and systems that can be used to form atransparent and/or translucent barrier layer that cooperates with alight extraction layer to both protect and enhance the function oflight-emitting devices such as organic light emitting diodes (OLEDs).The barrier layer is a thin, impermeable and mechanically robust layerthat can be formed immediately adjacent to the device. In oneembodiment, a separate light extraction layer can be formed over thebarrier layer. In a further embodiment, a light extraction layer can beincorporated into at least a portion of the barrier layer.

The barrier layer is formed from an inorganic, glass material such as atin fluorophosphate glass, tungsten-doped tin fluorophosphate glass,chalcogenide glass, tellurite glass, borate glasses, phosphate glassesor combinations thereof. The scattering layer may be a composite layerthat includes both a high refractive index matrix material and opticallytransparent particles that are incorporated into and throughout thematrix. The matrix material may comprise a polymeric material or aninorganic, glass material. Particles within the matrix material caninduce scattering of photons that pass into the scattering layer.

In addition to or in lieu of providing bulk scattering via embeddedparticles, the scattering layer may include a structured surface, suchas near-surface roughness, that can provide surface scattering. Thus,the light extraction layer according to particular embodiments comprisesa matrix material and a scattering layer, where the scattering layer isselected from the group consisting of scattering particles dispersedthroughout the matrix material and a roughened surface. The device canbe formed on a flexible substrate.

Additional features and advantages of the invention will be set forth inthe detailed description which follows, and in part will be readilyapparent to those skilled in the art from that description or recognizedby practicing the invention as described herein, including the detaileddescription which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description present embodiments of the invention,and are intended to provide an overview or framework for understandingthe nature and character of the invention as it is claimed. Theaccompanying drawings are included to provide a further understanding ofthe invention, and are incorporated into and constitute a part of thisspecification. The drawings illustrate various embodiments of theinvention and together with the description serve to explain theprinciples and operations of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of (A) a bottom-emission OLED device, and (B) atop-emission OLED device according to various embodiments;

FIG. 2 is a schematic of a top-emission OLED device according to anembodiment;

FIG. 3 is a schematic of a bottom-emission OLED device according to anembodiment;

FIG. 4 is a schematic of a top-emission OLED device according to afurther embodiment;

FIG. 5 is a schematic of a top-emission OLED device according to a stillfurther embodiment;

FIGS. 6A and 6B are plots of two successive heating-cooling cycles for abarrier layer formed on a silicon substrate;

FIGS. 7A is a schematic diagram and FIG. 7B is an optical micrographillustrating light extraction from an example OLED device; and

FIG. 8 is a plot of power versus position for OLED devices with andwithout a light extraction layer.

DETAILED DESCRIPTION

An organic light emitting diode is protected by a hermetic barrier layerthat is formed over the device. A light extraction layer is provided inconjunction with the barrier layer. In embodiments, the barrier layer isan inorganic layer and the light extraction layer comprises a compositelayer that includes a high refractive index matrix material and one orboth of (a) scattering particles dispersed throughout the matrixmaterial and (b) a roughened surface. A flexible device can include asingle hermetic barrier layer. The barrier layer is adapted to preventor inhibit the ingress of oxygen or moisture to the underlying device.The light extraction layer is adapted to obviate or significantlyinhibit the phenomenon of total internal reflection within the barrierlayer and, with it, the attendant light trapping during operation of thedevice. Volumetric and/or surface scattering introduced by the lightextraction layer can, in embodiments, enhance the output power from anOLED device by a factor of 2 or 3 or more.

The barrier layer may comprise a glass material selected from the groupconsisting of tin fluorophosphate glasses, tungsten-doped tinfluorophosphate glasses, chalcogenide glasses, tellurite glasses, borateglasses and phosphate glasses. The matrix material for the lightextraction layer may comprise the inorganic barrier layer or,alternately, a high refractive index inorganic or organic layer such aszirconium oxide or polyethylene terephalate (PET). Additional suitablematrix materials are disclosed herein. The scattering particles mayinclude transparent, inorganic particles that comprise a material havinga refractive index that is different than the refractive index of thematrix material.

In embodiments, active layers of the OLED may be formed on a flexiblesubstrate. An example flexible substrate material is polyethyleneterephalate (PET) optionally planarized with a thin PMMA film. Inembodiments, a barrier layer is formed immediately adjacent to the OLEDactive layers. The combination of the barrier layer and the lightextraction layer is lightweight, flexible, resilient, and is resistantto cracking and delaminating.

FIG. 2 illustrates an example embodiment of a top-emission OLED deviceaccording to one embodiment. The OLED device 200, which includes activelayers 4 such as electron transport layer 4 a and hole transport layer 4b and opposing electrodes 2 and 6 such as top electrode 2 and bottomelectrode 6 is formed on a supporting substrate 10. A barrier layer 8and a light extraction layer 12 are successively formed over the OLEDdevice. In the illustrated embodiment, the barrier layer is in directphysical contact with the OLED device and the light extraction layer isin direct physical contact with the barrier layer. The light extractionlayer 12 includes a plurality of scattering particles 14 embedded in ahigh refractive index matrix material 16.

FIG. 3 shows an example embodiment of a bottom-emission OLED structure300. A light extraction layer 12 is formed between an OLED devicestructure and a supporting substrate 10, and a barrier layer 8 is formedover the OLED device structure on one side of the substrate 10. Thelight extraction layer includes matrix material 16 and scatteringparticles 14 dispersed throughout the matrix material. In theillustrated bottom-emission structure, the bottom electrode 6 can be atransparent electrode such as an electrode comprising indium tin oxide(ITO).

A variant of the top-emission device of FIG. 2 is shown in FIG. 4. Thedevice 400 includes a barrier layer 8 formed over the device substrate.In the FIG. 4 embodiment, the barrier layer comprises a high refractiveindex inorganic material (e.g., glass material) and a plurality ofscattering particles 14 are dispersed throughout the barrier layer. Asillustrated, the barrier layer, which adapted to also serve a lightextraction function, can be in direct physical contact with the OLEDdevice.

FIG. 5 illustrates a further example embodiment of a top-emission OLEDstructure. In the FIG. 5 embodiment, the light extraction layer 12 isformed by roughening the free surface of the barrier layer 8.

In various embodiments, the barrier layer is transparent and/ortranslucent, thin, flexible, impermeable, “green,” and configured toform hermetic seals. In embodiments, the barrier layer is an inorganiclayer and is free of fillers and/or binders. Further, the materials usedto form the inorganic layer are not frit-based or powders formed fromground glasses. In further embodiments, the light extraction layer istransparent and/or translucent, thin, flexible, and configured to adhereto the barrier layer.

In embodiments, a low melting temperature glass can be used to form thebarrier layer. As used herein, a low melting temperature glass has asoftening point less than 500° C., e.g., less than 500, 400, 350, 300,250 or 200° C. In embodiments where the barrier layer comprises a glassmaterial, such glass can have a glass transition temperature of lessthan 400° C. (e.g., less than 400, 350, 300, 250, or 200° C.).

Exemplary materials that can form the barrier layer can include copperoxides, tin oxides, silicon oxides, tin phosphates, tinfluorophosphates, chalcogenide glasses, tellurite glasses, borateglasses, and combinations thereof.

Example compositions of suitable tin fluorophosphate glasses, forexample, include: 20-75 wt. % tin, 2-20 wt. % phosphorus, 10-46 wt. %oxygen, 10-36 wt. % fluorine, and 0-5 wt. % niobium. An example tinfluorophosphate glass includes: 22.42 wt. % Sn, 11.48 wt. % P, 42.41 wt.% O, 22.64 wt. % F and 1.05 wt. % Nb. Example tungsten-doped tinfluorophosphate glasses include: 55-75 wt. % tin, 4-14 wt. % phosphorus,6-24 wt. % oxygen, 4-22 wt. % fluorine, and 0.15-15 wt. % tungsten.Further example inorganic layer compositions, expressed in terms of molepercent of the constituent oxides, include 20-100% SnO, 0-50% SnF₂,0-30% P₂O₅ and as optional additions 0-10% WO₃ or 0-5% Nb₂O₅. Stillfurther example inorganic layer compositions include 20-100% SnO, 0-50%SnF₂, 0-30% B₂O₃ and as optional additions 0-10% WO₃ or 0-5% Nb₂O₅.

Additional aspects of suitable low melting temperature glasscompositions and methods used to form glass layers from these materialsare disclosed in commonly-assigned U.S. Pat. Nos. 8,115,326, 5,089,446,7,615,506, 7,722,929, 7,829,147 and commonly-assigned U.S. PatentApplication Publication Nos. 2007/0040501 and 2012/0028011 the entirecontents of which are incorporated by reference herein.

The inorganic barrier layer material may be deposited by, for example,sputtering, co-evaporation, laser ablation, flash evaporation, spraying,pouring, vapor-deposition, dip-coating, painting or rolling,spin-coating, or any combination thereof. A suitable workpiece caninclude an OLED device such as an OLED device formed on a flexiblesubstrate.

By way of example, the barrier layer can be formed via room temperaturesputtering of one or more suitable low melting temperature (LMT) glassmaterials or precursors for these materials. A description of asingle-chamber sputter deposition apparatus for forming the barrierlayer is provided in commonly-assigned US Patent Application No.13/660,717, the entire contents of which are incorporated by referenceherein. In embodiments, a thickness (i.e., as-deposited thickness) ofthe barrier layer can range from about 10 nm to 50 microns (e.g., about0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 3, 5, 10, 20 or 50 microns).

Defects such as pinholes in the barrier layer can be eliminated though aconsolidation step (for example, exposure to moisture treatment), toproduce a pore-free, gas and moisture impenetrable protective layer. Anoptional heat treatment step may be performed in a vacuum, or in aninert atmosphere, or under ambient conditions depending upon factorssuch as the composition of the inorganic material.

Various thermal, mechanical, optical and electrical properties of tworepresentative barrier layer compositions are summarized in Table 1together with corresponding data for high purity fused silica. Expressedin terms of mole percent of the constituent oxides, composition 1 is aniobium-doped tin fluorophosphate glass comprising 32.1% SnO, 32.9%SnF₂, 33.3% (NH₄)H₂PO₄ and 1.6% Nb₂O₅, and composition 2 is a tinfluorophosphate glass comprising 80% SnO and 20% P₂O₅.

TABLE 1 Properties of example inorganic barrier layer materials.Property Comp. 1 Comp. 2 Fused Silica Thermal conductivity (W/mK) 0.310.29 1.30 Mass density (g/cm³) 4.2 4.2  2.2 Specific heat at 30° C.(J/gK) 0.37 0.36 0.78 Thermal diffusivity (mm²/sec) 0.20 0.19 0.75Emissivity 0.65 0.75 0.8 CTE (ppm/° C.) 16-18 13-15 0.5 Young's modulus(GPa) 35 — 72.7 Refractive index (450-700 nm) 1.8 1.8  1.46 Dielectricconstant 9 — 3.8

In embodiments, the light extraction layer comprises a matrix materialand a scattering layer, the scattering layer selected from the groupconsisting of scattering particles dispersed throughout the matrixmaterial and a roughened surface.

The light extraction layer can include a polymeric matrix. Suitablepolymers for the light extraction layer include transparentthermoplastics such as poly(methyl methacrylate) (PMMA), polyethylenenaphthalate (PEN), polyethersulfone (PES), polycarbonate (PC),polyethylene terephthalate (PET), polypropylene (PP), orientedpolypropylene (OPP), and the like. The light extraction layer matrix canbe formed from a UV-curable resin.

The light extraction layer can comprise an inorganic material matrix.For instance, the matrix can include a low melting temperature glass. Inparticular embodiments, the light extraction layer comprises at least aportion of the barrier layer. A further example material for the lightextraction matrix is magnesium fluoride (MgF₂).

In embodiments, a thickness of the light extraction layer can range fromabout 200 nm to 10 microns (e.g., about 0.2, 0.5, 1, 2, 3, 5 or 10microns).

The light extraction layer may further comprise a plurality ofscattering particles dispersed throughout the matrix material.Scattering particles may be formed, for example, from aluminum oxide,silicon oxide, titanium oxide, zirconium oxide, niobium oxide, zincoxide, tin oxide or silicon nitride, as well as from combinationsthereof. The scattering particles may be formed from an opticallytransparent material. The plurality of scattering particles may beformed from a single composition, or scattering particles havingdifferent compositions may be incorporated into the light extractionlayer. The scattering particles may occupy from 1 to 75% by volume ofthe scattering layer, e.g., about 1, 2, 4, 10, 20, 50 or 75 vol. %.

In embodiments, a difference in the refractive index between thescattering particles and the matrix material is at least 0.001. Theparticles can function as photon scattering sites due to this finiterefractive index contrast. A high refractive index layer (e.g., barrierlayer or light extraction layer) has a refractive index of at least 1.4.Example high refractive index layers have a refractive index of about1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0. In embodiments, a high refractiveindex layer can have a refractive index of from 1.4 to 3. The scatteringparticles can have a refractive index of from 1.4 to 3, e.g., about 1.4,1.5, 1.6, 1.7, 1.8, 1.9 or 2.0. An average particle size of thescattering particles can range from about 10 nm to about 450 nm, e.g.,about 10, 20, 50, 100, 200, 250, 300, 400 or 450 nm.

Volumetric scattering by the light extraction layer can be affected byone or more of (a) a plurality of discrete transparent particlesdispersed throughout a matrix material and having a higher or lowerrefractive index than the matrix, (b) a monolayer or multilayers oftransparent particles deposited on the OLED device structure prior todeposition of the barrier layer, (c) transparent microcrystals formedwith the light extraction layer via devitrification, (d) bubbles, or (e)depositing a layer of scattering particles between adjacent matrixand/or barrier layers.

In addition to or in lieu of providing bulk scattering via embeddedparticles, the scattering layer may include a surface structure such asnear-surface roughness that can provide surface scattering. Surfaceroughness may be provided by random or patterned etching of the matrixmaterial (e.g., chemical or dry etching) or by patterned deposition ofan additional layer over, for example, a previously-formed barrierlayer. A suitable range of surface roughness values for the lightextraction layer includes an rms (R_(q)) surface roughness of at least50 nm, e.g., 50, 100, 200 or 500 nm.

The substrate on which the device is formed can be a glass, polymer ormetal substrate. Example substrate materials may include metals (e.g.,aluminum or stainless steel), thermoplastics (e.g., polyethylenenaphthalate (PEN), polyethersulfone (PES), polycarbonate (PC),polyethylene terephthalate (PET), polypropylene (PP), orientedpolypropylene (OPP), etc.), glasses (e.g., borosilicates) andsemiconductors (e.g., gallium nitride). The substrate may be a passivesubstrate or may include an active device. An example substrate can havea thickness of from 25 microns to 5 mm. It is within the scope of thepresent disclosure that the device may comprise a flexible substratesuch as a substrate that may be used to form a flexible display or inthe field of flexible electronics. A flexible glass substrate, forexample, can have a thickness of from 25 to 500 microns (e.g., 25, 50,100, 200 or 500 microns) and a bend radius of as low as 200 microns.

For certain applications, properties of the barrier and light extractionlayers can include dimensional stability, surface roughness, matched CTEamong the layers, toughness, transparency, thermal capability, andbarrier properties and/or hermeticity suitable, for instance, for activematrix display fabrication. In embodiments, the barrier layer and thelight extraction layer are each CTE-matched with the device substrate.For example, the absolute value of a difference in the CTE between anytwo of the barrier layer, the light extraction layer and the substratecan be at most 20 ppm/° C., e.g., at most a CTE difference of 20, 10, 5or 2×10⁻⁶/° C. Substrates comprising polymers such as PEN and PET haveCTE values of approximately 18×10⁻⁶/° C. and 17×10⁻⁶/° C., respectively,which are well-matched with the CTE values of example barrier layermaterials as disclosed herein.

Some examples of different devices that can be protected by a barrierlayer and a light extraction layer include light-emitting devices (e.g.,OLED devices), display devices (e.g., LCD displays), photovoltaicdevices, thin-film sensors, and evanescent waveguide sensors. Forinstance, the substrate may comprise a glass plate infiltrated withphosphor. The major surfaces of the substrate can be unroughened, whichmay be characterized by an arithmetic surface roughness, Ra, of lessthan 100 nm, e.g., less than 100, 50, 20 or 10 nm.

The formation of the inorganic barrier layer and the light extractionlayer, as well as any optional heat treatment step, can be performed ata relatively low temperature (e.g., less than 500° C. or less than 300°C.) in a vacuum or inert atmosphere. This is done to ensure that awater-free and/or oxygen-free condition is maintained throughout theencapsulation process. This can be especially important for robust,long-life operation of sensitive device components such as organicelectronics with minimal degradation.

A hermetic layer is a layer which, for practical purposes, is consideredsubstantially airtight and substantially impervious to moisture. By wayof example, the hermetic barrier layer can be configured to limit thetranspiration (diffusion) of oxygen through the barrier to less thanabout 10⁻² cm³/m²/day (e.g., less than about 10⁻³ cm³/m²/day), and limitthe transpiration (diffusion) of water through the barrier to about 10⁻²g/m²/day (e.g., less than about 10⁻³, 10⁻⁴, 10⁻⁵ or 10⁻⁶ g/m²/day).

A flexible layer is a layer capable of exhibiting, without breaking orspalling, a bend radius of less than 1 meter, e.g., less than 1, 0.5,0.2, 0.1 or 0.05 m. The bend radius of an example substrate (e.g., aflexible glass substrate) can be less than 30, 20, 10, 5, 2 or 1 cm, forexample. In further embodiments, the bend radius of a flexible substratemay be less than 1 cm, e.g., less than 1, 0.5, 0.2, 0.1, 0.05 or 0.02cm. A device comprising a flexible substrate, for example, canreliability operate for up to 200000 bending cycles.

In a test sample comprising a 1 inch×3 inch PEN substrate (DupontTeonex® Q56A, 500 gauge) provided with a 100 nm layer of ITO formed overthe substrate and a 2 micron tin fluorophosphate barrier layer formedover the ITO layer, the resistance of the ITO along the 3 inch length ofthe sample was about 250 Ω. A bend radius of the foregoing structure wasdetermined by monitoring the resistance of the ITO layer as the samplewas flexed in a two-point bend test, and a value of the bend radius wascorrelated to a 10% increase in the resistance. An average bend radiusfor the 2 micron barrier layer on the PEN substrate was about 12.2±3.5mm. This bend radius is smaller than the bend radius of foil andepoxy-based OLED structures by about a factor of 4. Both the barrierlayer and the ITO layer were deposited by sputtering at roomtemperature.

Residual stress in an as-deposited barrier layer can be relieved using arelatively low-temperature post-deposition annealing step. As a resultof thermal cycling from about 20° C. to 120° C. (heating and coolingrates of about 0.75° C./min), hysteresis in a 0.5 micron tinfluorophosphate barrier layer formed on a silicon substrate is evidentin FIG. 6A, which shows that an initial compressive stress in thebarrier layer (−15 MPa) is essentially eliminated after a first thermalcycle. The filled circles correspond to heating cycle data, and the opencircles correspond to cooling cycle data. No hysteresis in the stressprofile is observed in a second heating/cooling cycle (FIG. 6B). Thestress was measured using a KLA Tencor Flexus FLX-2900 wafer stressmeasurement system.

The light extraction phenomenon associated with the use of the lightextraction layer is illustrated with reference to the following example.

A tris(8-hydroxyquinolinato)aluminium (AlQ3) OLED layer was initiallydeposited on a glass substrate 10, followed by sputter deposition of aniobium-doped tin fluorophosphate glass barrier layer (composition 1).The structure was illuminated with a UV lamp (365 nm) to inducephotoluminescence from the AlQ3 layer 9.

To demonstrate that light is trapped in the high refractive indexbarrier layer and available for extraction, a 20 micron thick lightextraction layer was formed over a portion of the barrier layer 8. Thelight extraction layer included a matrix material of partiallystabilized zirconia comprising a plurality of discrete, sub-micronpolycrystalline domains 14 a. For the demonstration, an index-matchingoil layer 15 (n=1.775) was provided at the interface between the barrierlayer and the light extraction layer to ensure good optical contactbetween the layers.

A cross-sectional schematic illustration of the sample is shown in FIG.7A, and a plan-view photograph of the hexagonally-patterned AlQ3 layeris shown in FIG. 7B. A first region A of the barrier layer is covered bythe light extraction layer 12, and a second region B of the barrierlayer is uncovered by the light extraction layer 12.

Quantification of the light extraction was made by scanning asmall-aperture photodetector across the emitting surface of the AlQ3. Agreen filter was used to filter the UV light. The results with andwithout the light extraction layer are shown in FIG. 8. The measuredpower output from the covered first region (with the light extractionlayer) reaches a maximum of about 37 nW, which is about 260% greaterthan (2.6×) the power measured from the uncovered second region, whichreaches a maximum of about 14 nW.

As disclosed herein, the hermetic barrier layer, in combination with thelight extraction layer, can be used to form long-lived, high opticaltransmission, low power consumption, flexible and efficient OLEDdevices. The hermetic barrier layer and the light extraction layer mayfurther possess a low elastic modulus and bend radius, high refractiveindex and transmission in the visible, and, in the case of the barrierlayer, a low glass transition temperature, which can be leveraged tomodify internal stress within the barrier layer at low processingtemperatures.

As used herein, the singular forms “a,” “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to a “layer” includes examples having two or moresuch “layers” unless the context clearly indicates otherwise.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, examples include from the one particular value and/or to theother particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint.

Unless otherwise expressly stated, it is in no way intended that anymethod set forth herein be construed as requiring that its steps beperformed in a specific order. Accordingly, where a method claim doesnot actually recite an order to be followed by its steps or it is nototherwise specifically stated in the claims or descriptions that thesteps are to be limited to a specific order, it is no way intended thatany particular order be inferred.

It is also noted that recitations herein refer to a component being“configured” or “adapted to” function in a particular way. In thisrespect, such a component is “configured” or “adapted to” embody aparticular property, or function in a particular manner, where suchrecitations are structural recitations as opposed to recitations ofintended use. More specifically, the references herein to the manner inwhich a component is “configured” or “adapted to” denotes an existingphysical condition of the component and, as such, is to be taken as adefinite recitation of the structural characteristics of the component.

While various features, elements or steps of particular embodiments maybe disclosed using the transitional phrase “comprising,” it is to beunderstood that alternative embodiments, including those that may bedescribed using the transitional phrases “consisting” or “consistingessentially of,” are implied. Thus, for example, implied alternativeembodiments to a glass substrate that comprises a glass material includeembodiments where a glass substrate consists of a glass material andembodiments where a glass substrate consists essentially of a glassmaterial.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the present disclosurewithout departing from the spirit and scope of the invention. Sincemodifications combinations, sub-combinations and variations of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and their equivalents.

What is claimed is:
 1. A protected optical device comprising, a devicestructure provided on a substrate, a hermetic barrier layer formed overat least part of the device structure, and a light extraction layer,wherein the barrier layer comprises a glass material selected from thegroup consisting of a tin fluorophosphate glass, a tungsten-doped tinfluorophosphate glass, a chalcogenide glass, a tellurite glass, a borateglass and a phosphate glass and the light extraction layer comprises atleast a scattering layer comprising a material selected from the groupconsisting of aluminum oxide, silicon oxide, titanium oxide, zirconiumoxide, niobium oxide, zinc oxide, tin oxide, silicon nitride andcombinations thereof.
 2. The device according to claim 1, wherein thelight extraction layer further comprises a matrix material.
 3. Thedevice according to claim 1, wherein the device structure comprises anorganic light emitting diode.
 4. The device according to claim 1,wherein the substrate is a flexible substrate.
 5. The device accordingto claim 1, wherein a thickness of the substrate is from 25 microns to 5mm.
 6. The device according to claim 1, wherein a thickness of thebarrier layer is from 200 nm to 10 microns.
 7. The device according toclaim 1, wherein a refractive index of the barrier layer is from 1.4 to3.
 8. The device according to claim 1, wherein the barrier layercomprises a glass material having a glass transition temperature of lessthan 400° C.
 9. The device according to claim 1, wherein the barrierlayer comprises a glass material having a softening point of less than500° C.
 10. The device according to claim 1, wherein the barrier layercomprises a glass material including: 20-75 wt. % Sn, 2-20 wt. % P,10-36 wt. % O, 10-36 wt. % F, and 0-5 wt. % Nb.
 11. The device accordingto claim 1, wherein the barrier layer comprises a glass materialincluding: 55-75 wt. % Sn, 4-14 wt. % P, 6-24 wt. % O, 4-22 wt. % F, and0.15-15 wt. % W.
 12. The device according to claim 1, wherein the lightextraction layer is formed over the barrier layer.
 13. The deviceaccording to claim 1, wherein the light extraction layer is formed overthe substrate.
 14. The device according to claim 1, wherein the lightextraction layer comprises at least a portion of the barrier layer. 15.The device according to claim 1, wherein a thickness of the lightextraction layer is from 50 nm to 1 mm.
 16. The device according toclaim 2, wherein a refractive index of the matrix material is from 1.4to
 3. 17. The device according to claim 2, wherein a refractive index ofthe barrier layer is substantially equal to a refractive index of thematrix material.
 18. The device according to claim 1, wherein an averagerms surface roughness (Rq) of the scattering layer is greater than 50nm.
 19. The device according to claim 1, wherein the barrier layer isoptically translucent.
 20. The device according to claim 1, wherein thebarrier layer is optically transparent